Earth-boring tools for forming wellbores in subterranean earth formations may include cutting elements secured to a body. For example, fixed-cutter earth-boring rotary drill bits (also referred to as “drag bits”) include cutting elements that are fixedly attached to a bit body of the drill bit. Roller cone earth-boring rotary drill bits may include cones that are mounted on bearing pins extending from legs of a bit body such that each cone is capable of rotating about the bearing pin on which it is mounted. Cutting elements may extend from each cone of the drill bit.
The cutting elements used in such earth-boring tools often include polycrystalline diamond compact (PDC) cutting elements, also termed “cutters,” which are cutting elements including a polycrystalline diamond (PCD) material, which may be characterized as a superabrasive or superhard material. Such polycrystalline diamond materials are formed by sintering and bonding together relatively small synthetic, natural, or a combination of synthetic and natural diamond grains or crystals, termed “grit,” under conditions of high temperature and high pressure in the presence of a catalyst, such as, for example, cobalt, iron, nickel, or alloys and mixtures thereof, to form a layer of polycrystalline diamond material, also called a diamond table. These processes are often referred to as high temperature/high pressure (HTHP) processes. The polycrystalline diamond material may be secured to a substrate, which may comprise a cermet material, i.e., a ceramic-metallic composite material, such as, for example, cobalt-cemented tungsten carbide. In some instances, the polycrystalline diamond table may be formed on the cutting element, for example, during the HTHP sintering process. In such instances, cobalt or other catalyst material in the cutting element substrate may be swept among the diamond grains or crystals during sintering and serve as a catalyst material for forming a diamond table from the diamond grains or crystals. Powdered catalyst material may also be mixed with the diamond grains or crystals prior to sintering the grains or crystals together in an HTHP process. In other methods, however, the diamond table may be formed separately from the cutting element substrate and subsequently attached thereto.
As the diamond table of the cutting element interacts with the underlying earth formation, for example by shearing or crushing, the diamond table may delaminate, spall, or otherwise fracture because of the high forces acting on the cutting element and resulting high internal stresses within the diamond table of the cutting element. Some cutting elements may include non-planar interfaces, such as, for example, grooves, depressions, indentations, and notches, formed in one of the substrate and the diamond table, with the other of the substrate and the diamond table including corresponding, mating interface features. Illustrative non-planar interface designs are disclosed in, for example, U.S. Pat. No. 6,283,234, issued Sep. 4, 2001, to Torbet, U.S. Pat. No. 6,527,069, issued Mar. 4, 2003, to Meiners et al., U.S. Pat. No. 7,243,745, issued Jul. 17, 2007, to Skeem et al., and U.S. Pat. No. 8,020,642, issued Sep. 20, 2011, to Lancaster et al., the disclosure of each of which is incorporated herein in its entirety by this reference.